Pakistani authorities have closed all the schools in the country's largest province, Punjab, following an alert over possible militant attacks.

A government memo obtained by the Associated Press said there is intelligence that 13 Taliban fighters from neighbouring Afghanistan were planning suicide attacks on schools in Pakistan.

The province's education minister, Rana Mashood Ahmad, announced late on Monday that Punjab schools would remain closed till the end of the month.

He did not cite the government alert but said the closures were due to harsh winter weather and heavy fog in the province.

The warning comes a week after a breakaway Taliban faction attacked a north-western university and killed 21 people, mostly students. The university reopened briefly on Monday but then closed indefinitely to give students time to recover from the incident.